Ramzan Kadyrov, the outspoken leader of Chechnya, has threatened a judge over a decision to ban a piece of Islamic literature, and dared the country’s prosecutor general to punish him for it.

Kadyrov took to Instagram to condemn a decision made in August by a court in Yuzhno-Sakhalinsk in the far east of Russia to ban a work of Islamic literature called Supplication (Dua) to God: Its Meaning and Place in Islam.

According to a copy of the decision published by the online channel LifeNews, judge Natalya Perchenko ruled the work extremist because it included passages from the Qur’an “about the superiority and privilege of a person or groups over other people on the basis of their race, nationality or religion”, a decision that would ban it across Russia under controversial extremism laws.

Kadyrov called Perchenko and the state prosecutor “national traitors and devils” and said the decision must be reversed or he would deal with them personally.

“I demand a harsh punishment for the provocateurs who made this court decision and tried to blow up the situation in our country,” he wrote on Instagram. “If they don’t deal with them in the proper legal way, they will make me a criminal first of all. I personally CALL them to answer, because for me there is nothing higher in this life than the Qur’an.”

Kadryov uses Instagram to call for a harsh punishment for the Yuzhno-Sakhalinsk judges.

Russia’s prosecutor general’s office responded by saying it was “unacceptable to insult judges and prosecutors”, prompting Kadyrov to strengthen his previous statement.

He suggested the judge and prosecutor were “directly or indirectly working on behalf of hostile forces within the country or abroad” to foment unrest between Muslims and Russians of other faiths.

“Don’t appoint devils to the positions of prosecutor and judge, and then no one will call them that,” he wrote on Instagram. “I’m saying again that they’re devils and traitors. And those who don’t consider them that are also devils. And now punish me for that and make me change my opinion!”

Human rights experts say Russia’s vague and far-reaching extremism laws have often been misused against religious minorities, regime critics and independent media, and a number of opposition websites have recently been blocked on the pretence that they are extremist.

Several commentators including the Sova Centre, which studies xenophobia and extremism, and liberal Russian Orthodox deacon Andrei Kurayev agreed with Kadyrov and condemned the court’s decision to ban Supplication to God. Even a representative of a court said the ruling may have been mistaken.

Critics have accused the Kremlin of allowing Kadyrov to act with impunity and run the once-restive Chechnya as his own personal fiefdom in exchange for cracking down on the Islamist insurgencies there. He has been accused of widespread rights violations and heavy-handed tactics against opponents, which he denies.

Sergei Demidenko, an expert in Islam at Moscow’s Higher School of Economics, said the court’s decision seemed to have been made without proper analysis simply because some of the passages in question are central to Wahhabism, an 18th century movement that has inspired some contemporary Islamic militants.

“People see this and say this is Wahhabism, so we need to declare it extremist,” Demidenko told the Guardian. “They vaguely remembered that these were used by the Wahhabis, so they banned it.”